/**
* Creates an OAuth authorisation code.
*
* @param string $redirect_uri the redirect URI associated with the code
* @param string|array $scope the allowed scope - this should be a subset of
* the scope provided by the authorisation, or null if all of the authorisation's
* scope is to be included
* @param array $additional additional data to be stored in the code
* @return string the authorisation code
*/
public function issueCode($redirect_uri, $scope = null, $additional = array())
{
if ($scope == null) {
$scope = $this->available_scope;
}
$code = Code::create($this, $redirect_uri, $scope, $additional);
return $code->getCode();
}